Permanent magnet motor driven window lifter

Abstract

A motor drive for a window lifter in motor vehicle doors has an integrated flat housing containing a permanent magnet DC motor and a worm gear driven by a worm on the extended motor shaft; the housing has two halves which are separable in the plane of the motor axis and which serve as the return yoke of the motor. A single permanent magnet is arranged in the space defined on two sides essentially by the motor rotor on the one hand and the worm gear on the other hand and each of the two housing halves serves as a pole plate.

What is claimed is: 
     
       1. A motor drive useful in a window lifter for motor vehicles, having an integrated narrow housing comprising: (a) a substantially continuous hollow, non-magnetic frame;   (b) a permanent magnet DC motor comprising (1) a rotor;   (2) a single permanent magnet; and   (3) first and second pole plates for conducting flux from said magnet to opposite sides of said rotor, said pole plates in contact with said magnet on opposite sides thereof;     (c) a worm gear drive comprising: (1) a drive shaft extending from said rotor and connected to a worm;   (2) a worm gear which lies in the plane of the drive shaft engaging said worm;     (d) said single permanent magnet located adjacent to the rotor on the same side of the shaft as the worm gear and bounded on one side by said rotor on an adjacent side by said worm gear and on the side opposite said rotor by said hollow non-magnetic frame; and   (e) said pole plates being in the form of covers fastened to said frame on opposite sides of the rotor, magnet and worm gear, said covers and said continuous hollow non-magnetic frame thereby forming the housing for said motor drive.   
     
     
       2. The drive of claim 1, further comprising: the shaft being supported in the hollow frame; and   means for mounting brushes for the DC motor on the covers.   
     
     
       3. A motor drive in accordance with claim 2 having half-open bearing shells formed integrally with the frame for receiving the motor bearings and having a spring clip for clamping to the frame over the bearing opening for securing the bearing against radial motion in the shell. 
     
     
       4. A motor drive in accordance with claim 3 in which a spherical bearing, secured in a half-open bearing shell by a spring clip, and an axially adjacent thrust bearing provide support for the motor rotor shaft distant from the worm gear. 
     
     
       5. A motor drive in accordance with claim 1, having a partition separating the gear parts from the motor parts which is integrally formed with the frame. 
     
     
       6. A motor drive in accordance with claim 5, in which the pole plates and the frame form a substantially symmetrical housing relative to an axis of symmetry passing through the center of the worm gear and the support for the shaft of the motor at the end farthest away from the worm gear output shaft. 
     
     
       7. A motor drive in accordance with claim 6 in which tabs, punched and bent inward on the pole sheets, support hammerhead brush holders having mating counter-bearing surfaces on said tabs in the manner of knife edges, and springs connected to the pole sheets press each brushholder against a tab and against the commutator of the DC motor. 
     
     
       8. A motor drive in accordance with claim 7, in which the springs are connected to the pole plates by means of tabs punched and bent out of the plates.